Only Khaled can tell for sure but it's likely that literally nothing changed in the DCC routine.
A lot of people on mIRC 7.44 and mIRC 7.45 are using dcc send without any problem and you said it worked on 7.44 for a while.
These are very meaningful, it is likely your configuration that changed, for instance it could be your antivirus software causing it, could be some firewalls (windows/router).
The fact that it starts sending correctly and then stop suggests an AV software issue.
If you try to disable your AV software and install mIRC 7.45 in a new empty folder using the portable option, is it working?
Last edited by Wims; 13/05/16 05:53 PM.